Method and apparatus for tapping a blast furnace

ABSTRACT

A drill bit shaft member for tapping a hole in a blast furnace is disclosed. The drill bit shaft member comprises an elongate rod, a first fluid pressure inlet, a second fluid pressure inlet, a chamber in fluid communication with the first fluid pressure inlet and the second fluid pressure inlet, and an outlet in fluid communication with the chamber. A liquid and a gas are combined in the drill bit shaft member to form a mist to provide cooling for the drill bit shaft member. By cooling the drill bit shaft member, certain components that would normally be destroyed may be re-used.

RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. ProvisionalApplication Serial No. 60/451,510 for “Method and Apparatus for BoringThrough a Solid Material,” filed on Mar. 3, 2003.

TECHNICAL FIELD

[0002] The present invention relates to a method and apparatus forboring through a solid body. More particularly, the invention relates toan improved drill shaft with a liquid and gas mist cooling system toallow the drill shaft to be used multiple times.

BACKGROUND ART

[0003] There are different drill bits for drilling through a variety ofsolid materials. Many of these drill bits are designed for particularapplications. For instance, drill bits have been designed to drillthrough wood, metal, and concrete. In order to drill through thesedifferent materials, designers have varied the material used to producethe drill bits, the shape of the drill bits, and the speed with whichthe drill bit is operated.

[0004] One problem existing with many drill bits is the rate at whichthey will drill a hole is too slow. When the material to be drilled isdifficult to penetrate, the process of boring a hole may take as long asseveral minutes. It is often important be able to re-use components ofthe drill shaft to cut down on costs and increase profits. Such is thecase in drilling tap holes in metal purifying blast furnaces.

[0005] The first step in producing steel sheet, which is used in thebuilding and construction industry, the automotive industry, theappliance industry, the electric motor industry, etc., is to producerelatively pure iron from iron ore. This process is carried out within ablast furnace. In order to maximize the productivity of a steelmakingfacility, as much pure iron as possible must be produced. Many resourcesare expended in developing methods and procedures to increase the amountof pure iron which can be produced annually.

[0006] In developing these methods and procedures, every manufacturingvariable in the blast furnace process is optimized. One of thesevariables is the rate at which the blast furnace can be tapped to drainmolten iron from the furnace. A typical blast furnace is tapped fromseven to twelve times per day seven days per week. If a drill shaftbecomes damaged, the entire shaft must be replaced. The typical blastfurnace tap hole takes several minutes to drill. In fact, some tap holestake as long as 15 minutes to drill.

[0007] The drilling process is also slowed by drill bit binding. Bindingoccurs when loosened debris created in the drilling process buildswithin the hole. The debris accumulates around the drill bit and freezesthe drill bit within the hole preventing the drill bit from rotatingwithin the hole.

[0008] During the drilling process, extreme heat builds because offriction and because of the external temperature. Extreme heat, such asin a steel mill, can destroy multiple drill shafts while a single holeis being drilled. Additionally, the molten steel that exits through thehole also can destroy the drill shaft.

[0009] In order to solve some of these problems, certain drill bits havebeen designed which have fluid passages. Pressurized air is forcedthrough the passages toward the drill bit/solid body interface to coolthe shaft assembly and blow the debris away from the drill bit andprevent binding. However, when the hole to be drilled has a substantiallength, as is the case with a blast furnace tap hole, the debriscontinues to build because it cannot escape the hole. Additionally, theair does not provide effective heat transfer away from the drill shaft.

[0010] Prior art low-cost drill rods are described in U.S. applicationSer. No. 10/133,594 for “Method and Apparatus for Boring Through a SolidMaterial,” now U.S. Pat. No.______ , and PCT Publication No. WO 99/39076for “Method and Apparatus for Boring Through a Solid Material.”

[0011] The present invention is provided to solve these and otherproblems.

SUMMARY OF THE INVENTION

[0012] It is an object of the present invention to provide a drill bitshaft member for interconnection to a drilling apparatus. The drill bitshaft member comprises a first shaft member comprising a first elongaterod having a distal end and a proximal end. The proximal end has a firstfluid pressure inlet, a second fluid pressure inlet, a chamber in fluidcommunication with the first fluid pressure inlet and the second fluidpressure inlet, and an outlet in fluid communication with the chamber.

[0013] It is a further object of the present invention to provide asecond shaft member joined to the distal end of the first shaft member.The second shaft member comprises a second elongate rod having a fluidentrance and a fluid exit. The fluid entrance is in fluid communicationwith the outlet of the first shaft member and the fluid exit.

[0014] It is still a further object of the present invention to providea tubular sleeve axially disposed around the second elongate rod to forman open volume between the second elongate rod and the tubular sleeve. Afirst end of the tubular sleeve is adjacent to a first end of the secondelongate rod and joined to the second elongate rod to form a seal withthe second elongate rod.

[0015] It is still a further object of the present invention that thesecond elongate rod has a first port in fluid communication with thefluid entrance of the second elongate rod and the open volume.

[0016] It is still a further object of the present invention that thesecond elongate rod has a second port in fluid communication with theopen volume and the fluid exit of the second elongate rod.

[0017] It is still a further object of the present invention to providea drill bit joined to a second end of the second elongate rod. The drillbit is adapted for receiving a fluid pressure from the second shaftmember and delivering the fluid pressure to a drill site.

[0018] It is still a further object of the present invention that asecond end of the tubular sleeve opposite the first end of the tubularsleeve is adjacent to the drill bit.

[0019] It is still a further object of the present invention that asecond end of the tubular sleeve opposite the first end of the tubularsleeve abuts the drill bit.

[0020] It is still a further object of the present invention to providean exit port in the tubular sleeve in fluid communication with the openvolume.

[0021] It is still a further object of the present invention that thefirst fluid pressure inlet is axially disposed within the second fluidpressure inlet.

[0022] It is still a further object of the present invention that thefirst fluid pressure inlet delivers a liquid and the second fluidpressure inlet delivers a gas.

[0023] It is still a further object of the present invention to providea drill bit shaft member for interconnection to a drilling apparatus.The drill bit shaft member comprises an elongate rod comprising a firstfluid inlet, a second fluid inlet, a chamber in fluid communication withthe first fluid inlet and the second fluid inlet. A tubular sleeve isaxially disposed around the elongate rod to form an open volume betweenthe elongate rod and the tubular sleeve. A first end of the tubularsleeve is adjacent to a first end of the elongate rod and joined to theelongate rod to form a seal. A fluid exit is in fluid communication withthe chamber.

[0024] It is still a further object of the present invention that theelongate rod has a first port in fluid communication with the chamberand the open-volume.

[0025] It is still a further object of the present invention that theelongate rod has a second port in fluid communication with the openvolume and the fluid exit.

[0026] It is still a further object of the present invention to providean exit port in the tubular sleeve in fluid communication with the openvolume.

[0027] It is still a further object of the present invention that thefirst fluid pressure inlet is axially disposed within the second fluidpressure inlet.

[0028] It is still a further object of the present invention that thefirst fluid pressure inlet delivers a liquid and the second fluidpressure inlet delivers a gas.

[0029] It is still a further object of the present invention to providea low-cost method for drilling a tap hole in a blast furnace. Thelow-cost method comprises the steps of providing a first fluid pressuresource, providing a second fluid pressure source, and providing a drillshaft member comprising a first fluid pressure inlet, a second fluidpressure inlet, a chamber, and a fluid exit. The method furthercomprises the steps of providing a drill bit interconnected to the drillshaft member, introducing a first fluid pressure from the first fluidpressure source through the first fluid pressure inlet to the chamber,introducing a second fluid pressure from the second fluid pressuresource through the second fluid pressure inlet to the chamber, andmixing the first fluid pressure and the second fluid pressure within thechamber to form a mixture of the first fluid pressure and the secondfluid pressure. The mixture of the first fluid pressure and the secondfluid pressure is expelled through the fluid exit, and a drilling forceis provided to the drill bit.

[0030] It is still a further object of the present invention that thefirst fluid pressure inlet is axially disposed within the second fluidpressure inlet.

[0031] It is still a further object of the present invention that thefirst fluid pressure is a liquid and the second fluid pressure is a gas.

[0032] Other advantages and aspects of the invention will becomeapparent upon making reference to the specification, claims, anddrawings that follow.

BRIEF DESCRIPTION OF DRAWINGS

[0033]FIG. 1 is a cross-sectional view of a drill shaft of the presentinvention;

[0034]FIG. 2 is a view taken along 2-2 of FIG. 1;

[0035]FIG. 3 is a cross-sectional view of a drill shaft of the presentinvention;

[0036]FIG. 4 is a cross-sectional view of a drill shaft of the presentinvention;

[0037]FIG. 5 is a view taken along 3-3 of FIG. 4;

[0038]FIG. 6 is a cross-sectional view of a drill shaft of the presentinvention; and,

[0039]FIG. 7 is a perspective view of a drill bit of the presentinvention.

DETAILED DESCRIPTION

[0040] While this invention is susceptible of embodiment in manydifferent forms, there is shown in the drawings and will herein bedescribed in detail a preferred embodiment of the invention with theunderstanding that the present disclosure is to be considered as anexemplification of the principles of the invention and is not intendedto limit the broad aspect of the invention to embodiment illustrated.

[0041] Referring to FIG. 1, a drill bit shaft member 10 forinterconnection to a drilling apparatus is shown. The drill bit shaftmember 10 comprises a first shaft member 4 comprising a first elongaterod 7 having a distal end 6 and a proximal end 8. The proximal end 8 hasa first fluid pressure inlet 13, a second fluid pressure inlet 15, achamber 16 in fluid communication with the first fluid pressure inlet 13and the second fluid pressure inlet 15, and an outlet 14 in fluidcommunication with the chamber 16. The first elongate rod may be anextension piece, like those set forth in U.S. application Ser. No.10/133,594 for “Method and Apparatus for Boring Through a SolidMaterial,” now U.S. Pat. No.______ , which is hereby incorporated byreference herein.

[0042] The first fluid pressure inlet 13 is axially disposed within thesecond fluid pressure inlet 15. The first fluid pressure inlet 13delivers a liquid and the second fluid pressure inlet 15 delivers a gas.In order to provide cooling and prevent heat damage to the drill bitshaft member 10, the liquid and the gas are delivered into the chamber16, where they combine to form a mist, which mist can be used to coolthe system during drilling. In this embodiment, the liquid is introducedinto the drill bit shaft member 10 via first fluid inlet 13, which islocated in the first elongate rod 7, or optionally directly into thesecond elongate rod 3 (this embodiment not shown).

[0043] This mist exits the chamber 16 via the outlet 14 of the firstshaft member 4, and enters a second shaft member 2 that is joined to thedistal end 6 of the first shaft member 4. The second shaft member 2comprises a second elongate rod 3 having a fluid entrance 17 and a fluidexit 25. The fluid entrance 17 is in fluid communication with the outlet14 of the first shaft member 4 and the fluid exit 25. Therefore, themist exits through the outlet 14 and enters the second shaft member 2via the fluid entrance 17.

[0044] A tubular sleeve 5 is axially disposed around the second elongaterod 3 to form an open volume 21 between the second elongate rod 3 andthe tubular sleeve 5. A first end of the tubular sleeve 11 is adjacentto a first end of the second elongate rod 12 and joined to the secondelongate rod 3 to form a seal with the second elongate rod 3. There isan exit port 20 in the tubular sleeve 5 in fluid communication with theopen volume 21.

[0045] The second elongate rod 3 has a first port 19 in fluidcommunication with the fluid entrance 17 of the second elongate rod 3and the open volume 21, so the mist travels from the fluid entrance 17via the first port 19 to the open volume 21 that is created between thesecond elongate rod 3 and the sleeve 5. The second elongate rod 3 has asecond port 23 in fluid communication with the open volume 21 and thefluid exit 25 of the second elongate rod 3, so the mist travels from theopen volume 21 via the second port 23 to the fluid exit 25.

[0046] A drill bit 1 is joined to a second end 24 of the second elongaterod 3. The drill bit 1 is adapted for receiving a fluid pressure fromthe second shaft member 2 via the fluid exit 25 and delivering the fluidpressure to a drill site. The drill bit 1 has exit holes 27 locatedcircumferentially around the drill bit 1, as well as optionally at thetip 29.

[0047] Another type of drill bit 1 with a smaller pilot part 28 is shownin FIG. 7. The drill bit of FIG. 7 has the exit hole 27 at the tip 29.The drill bit 1 of FIG. 7 may also have one or a plurality of raisednodules 30 that assist in efficient drilling.

[0048] A second end of the tubular sleeve 18 opposite the first end ofthe tubular sleeve 11 may be adjacent to the drill bit 1. In FIG. 1, thesecond end of the tubular sleeve 18 opposite the first end of thetubular sleeve 11 abuts the drill bit 1. The first and second ends ofthe tubular sleeve 11,18 may optionally be swedged (shaped like circularcones) to provide a tighter fit to the drill bit 1 and first elongaterod 7.

[0049] Referring to FIG. 3, a drill bit shaft member 310 forinterconnection to a drilling apparatus is shown. The drill bit shaftmember 310 comprises an elongate rod 303 comprising a first fluid inlet313, a second fluid inlet 315, a chamber 331 in fluid communication withthe first fluid inlet 313 and the second fluid inlet 315. The firstfluid pressure inlet 313 is axially disposed within the second fluidpressure inlet 315. The first fluid pressure inlet 313 delivers a liquidand the second fluid pressure inlet 315 delivers a gas. In order toprovide cooling and prevent heat damage to the drill bit shaft member310, the liquid and the gas are mixed in the chamber 331 to form a mistthat cools the system during drilling.

[0050] A tubular sleeve 305 is axially disposed around the elongate rod303 to form an open volume 321 between the elongate rod 303 and thetubular sleeve 305. A first end of the tubular sleeve 308 is adjacent toa first end of the elongate rod 309 and joined to the elongate rod 303to form a seal.

[0051] A fluid exit 333 is in fluid communication with the chamber 331.There is an exit port 337 in the tubular sleeve 305 in fluidcommunication with the open volume 321. A first port 334 may be in fluidcommunication with the chamber 331 and the open volume 321. A secondport 335 may be in fluid communication with the open volume 321 and thefluid exit 333. Allowing mist to flow in the open volume 321 greatlyreduces the heat damage to the sleeve 305 and the elongate rod 303.

[0052] The liquid and the gas are directed into the drill bit shaftmember 310 via the first and second fluid inlets 313, 315, and combinedin the chamber 331 to form a mist. The first and second fluid inlets313, 315 may be located as shown, or in an extension piece (thisembodiment is not shown). Instead of using the first and second ports334, 335 to distribute the mist, the embodiment shown in FIG. 3 mayoptionally be made without the first and second ports 334, 335 (thisembodiment is not shown). This is because the chamber 331 extends thelength of the elongate rod 303, in other words, the elongate rod 303 isa hollow tube. This allows the mist to flow freely through elongate rod303 and via the fluid exit 333 to a drill bit 301. The drill bit 301 hasexit holes 327 located circumferentially around the bit as well asoptionally at the tip 329.

[0053] The elongate rod may take the form of a solid rod or a hollowtube. The second elongate rod 3 shown in FIG. 1 is an example of thesolid rod type, as can be seen from the cross-section shown in FIG. 2.The elongate rod 303 shown in FIG. 3 is an example of the hollow tuberod type. Depending upon the drilling situation if the hollow tube rodtype is chosen, thicker-walled tubing must be used to provide the properstrength for the rod. The tubular sleeve 5, 305 is typically a hollowtube, but may vary in thickness according to the requirements of eachjob.

[0054] The liquid and the gas are both pressurized to force the mist toflow through the drill bit shaft member 10, 310. The flow rate andpressure of the liquid and the gas are adjustable based on the heattransfer requirements for each job. If more heat needs to be removedfrom the drill bit shaft member 10, 310, the flow rates of the liquidand the gas can be increased accordingly. It has been found that,generally, the liquid pressure needs to be at least 10 psi greater thanthe gas pressure. The ratio of liquid pressure to gas pressure, as wellas liquid flow rate to gas flow rate, can be optimized to produce adesired mist consistency. In many locations, water pressure providedfrom a regular spigot and gas pressure provided by a portable compressoris sufficient to produce an adequate mist. Much higher pressures canalso be used to produce an adequate mist.

[0055] One of the novel aspects of the present invention is that theliquid and the gas are combined in the drill bit shaft member 10, 310,itself, instead of prior to entering the drill bit shaft member 10, 310as a premixed mist. One of the beneficial aspects of this method is thatthe mist should not flow back into the hammer or drill mechanism. Flowback is prevented by mixing the liquid and the gas in the drill bitshaft member 10, 310. Others have attempted to use water and airstreams, but have combined them prior to entering the drill rod. Inthose prior attempts, the water flows through the hammer itself andcauses corrosion and ice blockages during the winter. In manysituations, the chosen liquid is water and the chosen gas is air. Otherpossible liquids that may be utilized in the present invention includewater-based coolants. Other possible gases that may be utilized in thepresent invention include nitrogen and carbon dioxide. The choice ofliquid and gas components is dependent upon their availability, as wellas the situation in which the drill bit shaft member 10, 310 may beused. In some situations, it may be dangerous to use compressed airbecause of the oxygen content. In those situations, nitrogen gas may beused instead.

[0056] The mist acts as a heat carrier by absorbing heat from the drillbit shaft member 10, 310 and carrying it away from the drill bit shaftmember 10, 310 when it exits through either the drill bit 1, 301 or theexit ports 27, 327 located on the sleeve 5, 305. The quantity of heatremoved from the system is dependent upon the component chosen for thegas and liquid, as well as the flow rates of the components. An air andwater mist is an ideal mist because of its ability to carry and removeheat from the system. Most of the heat is removed from the system by theliquid component, such as water. Water has two important functions forremoving heat from the system. First, as a liquid and gas, water has aspecific heat capacity for absorbing heat. Second, a large amount ofheat is absorbed in the transformation of water from liquid to gas. Theheat that is absorbed is the heat of vaporization. These twoheat-absorbing functions, when combined, can remove a large amount ofheat from the system. These values will vary according to the pressureof the system.

[0057] Not only is an air and water mist excellent for removing heatfrom the system, but it is inexpensive and readily available in mostlocations where the present invention may be utilized. One location thatthe present invention may be utilized is in steel mills. Steel millsgenerally have either compressed air lines or portable compressors, aswell as water sources from a spigot. The water pressure can be increasedas needed with a pump.

[0058] Another embodiment of the present invention for protecting thedrill rod and interior shaft from heat damage consists of utilizing aninsulating layer. Referring to FIG. 4, a drill bit for boring a holethrough a solid body is illustrated. The drill bit 401 is shown joinedto an interior shaft 403 and abutting a sleeve 405. The interior shaftmay take the form of a solid rod or hollow tube. Depending upon thedrilling situation if tubing is chosen, thicker-walled tubing must beused to provide proper strength. The outer sleeve is typically a hollowtube, but may vary in thickness according to each job. The bit 401typically will attach to the interior shaft 403 and abut the sleeve 405.Between the interior shaft 403 and the sleeve 405, a paper pulp material441 is placed for insulation. Paper pulp material such as cardboard maybe utilized as an efficient insulator because its thermal conductivityis 0.07 W/mK whereas medium carbon steel is approximately 51.9 W/mK.This insulation prevents excessive heat from traveling from the sleeve405 to the interior shaft 403 during drilling.

[0059] Paper pulp materials are ideal for drill rod applications. Asevident from its thermal conductivity, cardboard is an inexpensiveinsulating material that will not conduct excessive heat as steel does.Paper pulp material is readily available, comes in various sizes and canalso be customized for unique applications. For example, cardboard canbe preformed to precisely fit around the interior shaft 403 but still besmall enough to fit inside the sleeve 405. Not only is the materialeasily shaped, but it is inexpensive. Other insulators, such aspolycarbonate may be utilized as well. The above embodiments, themisting system and the cardboard embodiment, may optionally be combined.

[0060] Additionally, the drill shaft utilized in the misting embodimentand cardboard embodiment may consist of extensions. Referring to FIG. 5,a base unit 551, an extension unit 553, and an end unit 555 may beutilized. The drill shaft 500 may exist with any number of extensions,or no extensions, as required for specific uses. In FIG. 6, notice thatonly the end unit 555 has an exterior sleeve 505 and an interior shaft503. This is because usually only the end of the drill shaft is soseverely damaged that it may not be re-used. Therefore, by having theend unit sleeved, minimal material is discarded after each use when thesleeve is destroyed. Also notice that the ends of the exterior sleeveare swedged to provide a tighter seal at the sleeve/drill bit interfaceand the sleeve/extension or base interface. The sleeve merely abuts theother pieces at these interfaces and is held in place by compressionwhen the drill bit is attached.

[0061] When utilizing a mist, the first and second fluid inlets 13, 313,15, 315 may extend through the entire drill bit shaft member 10, 310, oronly partially. Depending on external temperatures, and heat transferrequirements, it may be desired to combine the liquid and gas to formthe mist at a specific portion of the shaft.

[0062] Additional improvements have been made to prevent damage to thedrill bit shaft member 10, 310 of the present invention. For example,typically, the tubular sleeve 5, 305 was significantly smaller than thedrill bit 1, 301 head. This created a problem because it allowed a largespace for molten steel to flow when the drill hole was finished but thedrill bit shaft member 10, 310 had not yet been removed. By increasingthe size of the sleeve 5, 305, so that it is only slightly smaller thanthe drill bit, the volume of molten steel that flows around the drillbit shaft member 10, 310 is limited, thus minimizing damage. Forexample, the sleeve 5, 305 could be 0-20% smaller, or more preferably0-10% smaller than the drill bit 1, 301 head, or any range orcombination of ranges therein.

[0063] Another improvement was made by increasing the length of thedrill bit 1, 301. As described above, when the hole is complete, moltensteel flows around the drill bit shaft member 10, 310. By lengtheningthe bit 1, 301, which is usually destroyed during each use, theremaining pieces of the drill bit shaft member 10, 310 may sometimes besaved and re-used.

[0064] Another aspect of the present invention is that the interiorelongate rod 3, 303 is not welded to the sleeve 5, 305. Typically, theinterior elongate rod 3, 303 was welded to the sleeve 5, 305 to providea permanent leak-proof fit. By allowing the sleeve 5, 305 to be removedfrom the interior elongate rod 3, 303, the interior elongate rod 3, 303may be re-used while the sleeve 5, 305 may be discarded.

[0065] It is still a further object of the present invention to providea low-cost method for drilling a tap hole in a blast furnace. Thelow-cost method comprises the steps of providing a first fluid pressuresource, providing a second fluid pressure source, and providing a drillshaft member 10 comprising a first fluid pressure inlet 13, a secondfluid pressure inlet 15, a chamber 16, and a fluid exit 25. The methodfurther comprises the steps of providing a drill bit 1 interconnected tothe drill shaft member 10, introducing a first fluid pressure from thefirst fluid pressure source through the first fluid pressure inlet 13 tothe chamber 16, introducing a second fluid pressure from the secondfluid pressure source through the second fluid pressure inlet 15 to thechamber 16, and mixing the first fluid pressure and the second fluidpressure within the chamber 16 to form a mixture of the first fluidpressure and the second fluid pressure. The mixture of the first fluidpressure and the second fluid pressure is expelled through the fluidexit 25, and a drilling force is provided to the drill bit 1. The firstfluid pressure inlet 13 may be axially disposed within the second fluidpressure inlet 15. The first fluid pressure may be a liquid and thesecond fluid pressure may be a gas.

[0066] Several alternative embodiments have been described andillustrated. A person of ordinary skilled in the art would appreciatethat the features of the individual embodiments, and the possiblecombinations and variations of the components. A person of ordinaryskill in the art would further appreciate that any of the embodimentscould be provided in any combination with the other embodimentsdisclosed herein. Further, the terms “first,”“second,” “proximal,”“distal,” etc. are used for illustrative purposes only and are notintended to limit the embodiments in any way, and the term “plurality”as used herein is intended to indicate any number greater than one,either disjunctively or conjunctively as necessary, up to an infinitenumber.

[0067] While specific embodiments have been illustrated and described,numerous modifications come to mind without significantly departing fromthe spirit of the invention and the scope of protection is only limitedby the scope of the accompanying claims.

We claim:
 1. A drill bit shaft member for interconnection to a drillingapparatus, the drill bit shaft member comprising: a first shaft membercomprising a first elongate rod having a distal end and a proximal end,the proximal end having a first fluid pressure inlet, a second fluidpressure inlet, a chamber in fluid communication with the first fluidpressure inlet and the second fluid pressure inlet, and an outlet influid communication with the chamber.
 2. The drill bit shaft member ofclaim 1 further comprising: a second shaft member joined to the distalend of the first shaft member, the second shaft member comprising asecond elongate rod having a fluid entrance and a fluid exit, the fluidentrance in fluid communication with the outlet of the first shaftmember and the fluid exit.
 3. The drill bit shaft member of claim 2further comprising: a tubular sleeve axially disposed around the secondelongate rod to form an open volume between the second elongate rod andthe tubular sleeve, a first end of the tubular sleeve adjacent to afirst end of the second elongate rod and joined to the second elongaterod to form a seal with the second elongate rod.
 4. The drill bit shaftmember of claim 3 wherein the second elongate rod has a first port influid communication with the fluid entrance of the second elongate rodand the open volume.
 5. The drill bit shaft member of claim 4 whereinthe second elongate rod has a second port in fluid communication withthe open volume and the fluid exit of the second elongate rod.
 6. Thedrill bit shaft member of claim 5 further comprising: a drill bit joinedto a second end of the second elongate rod, the drill bit adapted forreceiving a fluid pressure from the second shaft member and deliveringthe fluid pressure to a drill site.
 7. The drill bit shaft member ofclaim 6, wherein a second end of the tubular sleeve opposite the firstend of the tubular sleeve is adjacent to the drill bit.
 8. The drill bitshaft member of claim 7 wherein the second end of the tubular sleeveabuts the drill bit.
 9. The drill bit shaft member of claim 8 furthercomprising: an exit port in the tubular sleeve in fluid communicationwith the open volume.
 10. The drill bit shaft member of claim 1 whereinthe first fluid pressure inlet is axially disposed within the secondfluid pressure inlet.
 11. The drill bit shaft member of claim 1 whereinthe first fluid pressure inlet delivers a liquid and the second fluidpressure inlet delivers a gas.
 12. A drill bit shaft member forinterconnection to a drilling apparatus, the drill bit shaft membercomprising: an elongate rod comprising a first fluid inlet, a secondfluid inlet, a chamber in fluid communication with the first fluid inletand the second fluid inlet, a tubular sleeve axially disposed around theelongate rod to form an open volume between the elongate rod and thetubular sleeve, a first end of the tubular sleeve adjacent to a firstend of the elongate rod and joined to the elongate rod to form a seal,and a fluid exit in fluid communication with the chamber.
 13. The drillbit shaft member of claim 12 wherein the elongate rod has a first portin fluid communication with the chamber and the open volume.
 14. Thedrill bit shaft member of claim 13 wherein the elongate rod has a secondport in fluid communication with the-open volume and the fluid exit. 15.The drill bit shaft member of claim 14 further comprising: an exit portin the tubular sleeve in fluid communication with the open volume. 16.The drill bit shaft member of claim 12 wherein the first fluid pressureinlet is axially disposed within the second fluid pressure inlet. 17.The drill bit shaft member of claim 12 wherein the first fluid pressureinlet delivers a liquid and the second fluid pressure inlet delivers agas.
 18. A low-cost method for drilling a tap hole in a blast furnace,the low-cost method comprising the steps of: providing a first fluidpressure source; providing a second fluid pressure source; providing adrill shaft member comprising a first fluid pressure inlet, a secondfluid pressure inlet, a chamber, and a fluid exit; providing a drill bitinterconnected to the drill shaft member; introducing a first fluidpressure from the first fluid pressure source through the first fluidpressure inlet to the chamber; introducing a second fluid pressure fromthe second fluid pressure source through the second fluid pressure inletto the chamber; mixing the first fluid pressure and the second fluidpressure within the chamber to form a mixture of the first fluidpressure and the second fluid pressure; expelling the mixture of thefirst fluid pressure and the second fluid pressure through the fluidexit; and, providing a drilling force to the drill bit.
 19. The low-costmethod of claim 18 wherein the first fluid pressure inlet is axiallydisposed within the second fluid pressure inlet.
 20. The low-cost methodof claim 18 wherein the first fluid pressure is a liquid and the secondfluid pressure is a gas.